During the operation of a snubbing jack or rig assist unit, it is sometimes necessary to use the unit's powered rotary to drill or mill out material down-hole. The slip bowls that are used to hold the drill pipe (i.e., in the vertical direction) are not rated to handle torque. Because of this, a milling clamp is typically employed to transmit the torque from the rotary to the drill pipe/casing.
The most prevalent type of milling clamp currently used in the oil field industry today is a manual milling clamp that consists of a collar with set screws or T-bolts that are tightened against the pipe in order to transmit torque. Using such manual milling clamps may be labor-intensive, time consuming and/or inconvenient. A need therefore exists, for a milling clamp that is more convenient and less labor-intensive and time consuming to use.